A conventional oil purifying apparatus, such as that disclosed in Patent Literature 1, is equipped with: a superheated steam generating device for generating superheated steam; a heat treatment container (heating furnace) such as, for example, a rotary kiln for accommodating an organic substance and thermally decomposing the organic substance with the superheated steam supplied from the superheated steam generating device; and a piping facility for supplying the superheated steam from the superheated steam generating device to the heat treatment container. This piping facility is equipped with: a piping structure for connecting the superheated steam generating device and the heat treatment container; and a heating mechanism for keeping a temperature of the superheated steam passing through the piping structure to be a desired temperature, and the like.
In the oil purifying apparatus of a conventional configuration, however, in addition to requiring a heat quantity to be applied to the superheated steam generating device and the heat treatment container and a heat quantity to be applied to the heating mechanism, a ratio of a heat quantity of produced oil (recovered heat quantity) to the heat quantity applied to the entire oil purifying apparatus (applied heat quantity) is small, and therefore practical use thereof is hindered.